Soundproofing or sound-absorbing material

ABSTRACT

The described and claimed soundproofing material is planar and has an inhomogeneous structure. It consists of a textile or mesh having relatively thick, adjacent longitudinal components and relatively thin components running in the transverse direction at a spacing from one another. Longitudinal microslits are formed between the longitudinal components by the distribution of the thin transverse components. The width of the microslits amounts to 0.01 and 0.4 mm, and the thickness of the longitudinal components amounts to at least five to ten times that of the microslits.

FIELD OF THE INVENTION

The present invention relates to a soundproofing or sound-absorbing material of an essentially flat structure exhibiting microslits therein. Said material is designed for manufacturing soundproofing or sound-absorbing objects or their precursors. The invention furthermore relates to a preferred method of manufacturing such materials.

PRIOR ART

Soundproofing or sound-absorbing structures, referred to in the following as “sound absorbers” for short, are used in many different fields to minimize disruptive noises. Sound absorbers have become necessary because human hearing is sensitive and can be damaged by excessively strong sound pressure or even by certain sound frequencies; loud noises or sounds at certain frequencies, even far below the damage threshold, are perceived as disturbing and impair the quality of life.

Sound absorbers as such are already known in the most diverse embodiments. For example, they can be a structure made from fibers, open-cell polymer foams, glass fiber mats, or sprayed-on layers (usually of polyurethane foam) or acoustic tiles. The noise-reducing effect of fibrous sound absorbers is based on a frictional distribution of the sound energy, which is in turn based on air pressure variations within the fibrous structure. Despite the advantages of broadband absorption of sound by these fibrous or foam structures, they also exhibit unpleasant disadvantages, namely the dislodging of particles which have broken off and the atmospheric pollution resulting therefrom. Therefore, the use of such sound absorbers is often very limited.

In recent years, another type of sound absorber has become known, namely perforated solid panels. These sound absorbers usually exhibit relatively thick perforated substrates, for example of metal, and the perforations consist of relatively large holes; i.e. with a diameter greater than 1 mm. Two types of these panel-like sound absorbers are generally used, namely those comprising a sound-reflecting surface and absorbing a narrow sound frequency band in the audible range, and others as mechanical and absorbent support for a fibrous sound absorber over a wide frequency spectrum. In this case, the perforated panels serve as a support structure and the fibrous materials function as sound absorbers.

Microperforated structures have also already been proposed as sound absorbers. Such structures (see the U.S. Pat. No. 6,194,052 B1 and WO 2006/101403 A1 documents) take the form of perforated or slit panels, are relatively thick (for example thicker than 2 mm), and provided with mechanisms (reinforcements, beads, etc.) to prevent vibrations from the acoustic waves. A microperforation in the sense of present-day technical practice refers to the diameter or width of the perforation being within a range of 0.05 to 0.5 mm (iVT International 2005, p. 105-107 and WO 2006/101403 A1; 0.01 to 0.8 mm according to U.S. Pat. No. 6,194,052 B1).

For example, the U.S. Pat. No. 5,700,527 patent specification describes a sound-absorbing component made of glass or synthetic glass having a thickness of 0.2 to 30 mm and perforations having a diameter of 0.1 to 2.0 mm arranged at a 2 to 20 mm spacing from one another. These panels are to be disposed on the walls, ceilings or doors of buildings to serve as sound absorbers.

It has now been found that the manufacture of microperforated structures to act as sound absorbers is difficult and costly. In the U.S. Pat. No. 6,194,052 document, the individual perforations are not punched out as microslits but instead pressed out of the material using press tools, which leaves behind edges. The sound-absorbing panels according to the WO 2006/101403 document are cut out using a laser tool; this method is however limited to specific materials (metals, etc.). It is alternatively proposed to adjacently arrange a plurality of very narrow panels at a distance corresponding to the width of the microslits; this option is of course excluded in practice.

Important during manufacture is producing holes having smooth edges; when the edges are not smooth, as can be observed for example in the case of perforating metal or plastic sheets, the sound-absorbing effect suffers. A special machine is also required to perform the perforating, which increases the manufacturing costs. Nor is it possible to provide microperforations in fibrous structures as already being used as sound absorbers.

DISCLOSURE OF THE INVENTION

The invention is based on the task of overcoming the disadvantages of known microperforated structures, regardless of whether they are panels or films of any of the most diverse materials, and providing a new, economically-produced and highly sound-absorbing material which can be used as such or, after the appropriate configuring, as a sound absorber.

The inventive material is defined in the first independent claim and a preferred method for its manufacture forms the object of the second independent claim. Preferred or specific embodiments are set forth in the dependent claims.

The term “essentially flat structure” as used in this document refers to a two-dimensional expansion, as present for example in most textile materials, but which can also be undulating and exhibit peaks and valleys without losing its overall impression of flatness.

The term “inhomogeneous” as used in this document refers to a structure composed of at least two different source materials or having different visual and/or structural properties in the longitudinal and transverse directions and in particular differing from film or panels.

The inventive sound-absorbing material is a textile, a mesh or any other material consisting of at least two different source materials. The difference can be based on the material itself and/or its dimensions and/or forms. It has been found that sound-absorbing effect increases with increasing hardness to the components of the inventive material. For example, glass fibers or metal fibers are well suited as source materials. But all source materials which are in the form of filaments or fibers, or which can be brought into such form, and made from all suitable natural or synthetic materials including metals, a listing of which would be far too exhaustive here, can be used.

The inventive material is generally manufactured by weaving or interlacing, wherein the source material is to be selected on the one hand such that the desired microslits form in the course of the manufacturing process and, on the other, other unwanted perforations are either not produced or can be eliminated. This approach calls for suitably selecting the source materials. In the process, the invention excludes using the same source materials; thus no inventive materials can be obtained by normal weaving using identical warp and weft fibers since no microslits can be formed in this way, rather either no through-holes whatsoever form in tightly-meshed textiles or quasi-square holes form in normal or loosely-meshed materials.

For example, flat filaments of relatively low flexibility can be used as warp threads and coalesced into textile surface structures by means of thin, flexible fibers or filaments serving as weft and incorporated at a distance from one another. The horizontal spacing of the warp filaments, which at the same time define the width of the microslits, is determined by the thickness of the weft fibers or filaments, and the spacing between two successive weft fibers or filaments then corresponds to the length of the microslits. Devices for manufacturing such mesh-like structures are known; machines already in use could easily be adapted to the requirements of manufacturing the new material.

The above remarks clearly indicate that the inventive material is extremely simple and economical to manufacture compared to the prior art methods.

If desired, the inventive material can undergo processing prior to, during or subsequent to manufacture. This would include finishing same so as to increase the sound-absorbing effect, fire-retardant finishings, preservative agents, dyes, anti-corrosive agents for metallic materials, light stabilizers, curing agents for setting the material structure and many others known to experts in this field. Of course deforming the flat material manufactured is also among the possibilities, for example into sound-absorbing molded parts for automobiles, airplanes, ships, etc. or into other three-dimensional structures such as corrugated matting, reed matting, etc.

Most of the dimensions of the new material can vary over a wide range. The length and width of the inventive structure are only limited by the possibilities afforded by the respective manufacturing equipment. The thickness of the material is regulated by the required stability. When preferably rigid, break/tear-resistant lead fibers or filaments are to be employed, as is preferred for the better soundproofing of such materials, one obtains a quite thin but yet firm structure, generally having a thickness amounting to between 1 and 10 mm, preferably 1 to 5 mm. It is however thoroughly conceivable to also manufacture thinner materials.

When necessary, thin inventive materials can be affixed or mounted to supporting structures. The dimensions of the inventive material's microslits are between 1 and 20 mm in length and between 0.01 and 0.4 mm in width, whereby occasionally exceeding these values is also within the inventive scope.

In terms of a structure which is also mechanically resistant, the longitudinally-extending components should be as rigid as possible and barely undulated, while the transverse components are thinner and more flexible and wrap around the longitudinal components. That means that the microslits are to run as linearly as possible. Yet the microslits can of course also run in any desired direction such that the present invention is by no means limited to just linear microslits. To this end, at least a 5:1 thickness ratio of longitudinal to transverse components is preferred, more preferable is (5-10):1.

When manufacturing the new material, unwanted openings or holes can occur, as usually do in loosely-woven textiles, should the source materials allow it. These holes are called parasitic holes. They interfere with the absorption of sound and are generally eliminated by simply pressing the material between pressure rollers, the surface of which can also be structured. A condition here is compressibility of the fibers or threads used; if the new materials are to be produced with correspondingly-adapted profiled fibers or filaments, no parasitic gaps will develop.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in greater detail using embodiments referencing the drawings.

The drawings show:

FIG. 1 a perspective view of a first embodiment in which small profiled rods are interlaced by means of filaments;

FIG. 2 a perspective view of a second embodiment in which small profiled rods are interlaced by means of filaments;

FIG. 3 a perspective view of a third embodiment in which round rods are interlaced by means of filaments;

FIG. 4 a perspective view of a fourth embodiment in which round rods are interlaced by means of fibers;

FIG. 5 a cross-section along the V-V line from FIG. 4; and

FIG. 6 a perspective view of a fifth embodiment resulting from the undulating deformation of the material of the third embodiment as shown in FIG. 3.

EMBODIMENTS OF THE INVENTION

FIG. 1 shows four adjacently parallel profiled rods 10A, 10B, 10C and 10D exhibiting a hexagonal cross-section, having for example a lower and upper lateral width 18 of 0.5 to 10 mm. The profiled rods continue to the right and left of rods 10A and 10D. The rods are interlaced by filaments 12A, 12, wherein filament 12A extends over the first rod 10A, then under the second rod 10B, over the third rod 10C, under the fourth rod 10D, etc. Filament 12B is parallel to filament 12A at a spacing 16 and follows a reverse pattern (under 10A, over 10B, under 10C, over 10D, etc.). When the thickness 20 of filament 12A, 12B, etc. amounts to 0.1 mm, microslits are produced in area 22 which have a length 16, namely the distance between two consecutive filaments, and a width 20, namely the thickness of the filament, 0.1 mm in the present case. It is of course also possible to produce larger or smaller microslits according to need.

For example, the width 14 of filaments 12 amounts to 5 to 10 mm and the interspacing 16 between two consecutive filaments is likewise 5 to 10 mm. However, completely different dimensions are also possible in conjunction hereto. The material of profiled rod 10 can be a thermoplastic material and the filaments 12 can be composed of glass fibers.

The microslits 22 are distributed evenly and throughout the depicted areal mesh. However, other embodiments seeking a non-uniform distribution of the microslits across the mesh are also conceivable.

The structure according to FIG. 1 is manufactured by methods which are known per se. It is thereby possible to work with known weaving methods when the elasticity of the rods 10 allows same. Equally-wide, thinner filaments of water-soluble material (e.g. polyvinyl alcohol) can be woven as wefts between each two consecutive filaments 12 serving as weft; when the process is complete, these separation filaments can be dissolved away in water, resulting in a material with microslits of precise equal lengths.

FIG. 2 shows a perspective representation of a similar arrangement of rods and filaments. The profiled rods have a rectangular cross-section with a width B of 0.5 to 5 mm and a height H of 0.2 to 2 mm. They are held together by alternating fibrous material filaments 30; the width of the microslits 32 between each two parallel-spaced filaments 30 corresponds to the width of said filaments 30; said width M is about 0.1 mm in the present example.

FIG. 3 shows a material structured analogously to that of FIGS. 1 and 2, namely with profiled rods 40, here having a circular cross-section, and alternating filaments 42 running at parallel distances, also analogously here to FIGS. 1 and 2. Given an equal thickness D2 to filaments 42, the thickness D of the rods 40 amounts to 0.3 to 1 mm and the width M1 of the microslits 0.05 to 0.1 mm. Again, the given dimensions can vary so that thicker or thinner rods and correspondingly smaller or larger microslits are also possible. Also conceivable is a solution in which the rods are not circular but rather elliptical.

FIG. 4 shows an embodiment of the inventive material in which more or less thin rods 50 extending in the warp direction are incorporated by means of parallel-spaced and alternating weft fibers 52. As can be seen from FIG. 5, which shows a cross-section of the plane indicated by the V-V line, the rods 50 have a thickness D4 of 0.5 mm. They can thus be deemed thick fibers. The thickness D3 of the weft fibers, and thus also the width M2 of microslits 54, is e.g. 0.1 mm. The length of the microslits 54 depends on the interspacing of the weft fibers 52 (in the warp direction) and can be selected to be between 1 and 20 mm, in particular between 1 and 5 mm.

Finally, FIG. 6 shows a material in a schematic, perspective representation and as a fifth embodiment of the present invention in which the sound-absorbing product pursuant to FIG. 3 has been given an undulating or zigzagged structure by the longitudinal deformation of the rods or fibers 40 running in the warp direction. Doing so preserves the existing microslits and the structure is characterized by even greater improved sound-absorbing properties and increased mechanical stability.

The inventive material can be directly used, e.g. to manufacture sound-absorbing curtains, etc. Moreover, a high absorption of sound can be ensured with a very thin layer; in contrast hereto, the general rule with conventional acoustic insulating elements is the thicker, the better.

The embodiments of the invention discussed and depicted are only examples serving for a better understanding and do not limit the invention which is solely defined by the scope of the claims. Many improvements and further developments are possible and readily lend themselves to one skilled in the art. It is thus evident that using different materials in the manufacture will enable different dimensions and different profiles to the rods, filaments and fibers and enable other parameters to be appropriately selected so as to adapt the inventive materials and structures to many applications, a listing of which would be far too exhaustive here. The invention can be used wherever it is desired or necessary to diminish existing or expected noise emissions or reduce them to an inaudible level. 

1. A soundproofing material having an essentially flat structure exhibiting microslits therein, characterized in that it exhibits an essentially flat and inhomogeneous structure having components which extend in the longitudinal and the transverse direction of the material, wherein the microslits run in the longitudinal direction and constitute interspace sections between the longitudinal components of the material, and wherein the successive longitudinal microslits are separated from one another by transverse components of the material.
 2. The soundproofing material according to claim 1, characterized in that it is a mesh or a textile, wherein the longitudinal or warp components differ from the transversal or weft components, and wherein the longitudinal components, only separated by the transverse components, are arranged closely together and the transverse components run at a parallel and alternating spacing from one another.
 3. The soundproofing material according to claim 1, characterized in that the thickness of the transverse components, which essentially equals the width of the microslits, ranges from 0.01 to 0.2 mm.
 4. The soundproofing material according to claim 1, characterized in that the length of the microslits, which corresponds to the interspacing of the transverse components in the longitudinal direction, ranges from 1 to 20 mm.
 5. The soundproofing material according to claim 1, characterized in that the transverse components consist of flexible filaments.
 6. The soundproofing material according to claim 1, characterized in that the transverse components consist of fibers.
 7. The soundproofing material according to claim 1, characterized in that the longitudinal components consist of relatively rigid profiled rods or fibers having a thickness amounting to at least five times, preferably five to ten times that of the transverse components.
 8. The soundproofing material according to claim 1, characterized in that the longitudinal components are relatively rigid and barely undulated, while the transverse components are thinner and more flexible and wrap around the longitudinal components, whereby the microslits essentially extend without warping.
 9. The soundproofing material according to claim 1, characterized in that the components of the material consist of glass fibers or of metal.
 10. A method for manufacturing the soundproofing material according to claim 1, characterized in that parallel longitudinal components in the form of profiled rods or fibers in the longitudinal direction are connectively woven or interlaced together by means of transverse components in the form of filaments or fibers, wherein the longitudinal components are adjacent to one another and only separated from one another by the transverse components alternatingly incorporated over and under the longitudinal components as well as at a distance from one another so that microslits are produced between the longitudinal components.
 11. The method according to claim 10, characterized in that the components are selected so that the thickness of the longitudinal components is at a (5-10):1 ratio to the transverse components.
 12. The method according to claim 10, characterized in that unwanted parasitic gaps between the components, which differ from the microslits, and which can occur at those points where components intersect can be closed by pressing or rolling the material obtained. 